Field of the Invention
The invention concerns apparatus for cutting or milling bricks or building blocks; particularly for a horizontal or face milling of two opposing planes of hollow building blocks.
For the purpose of maintaining specific dimensions and for the provision of grooves, bricks, in particular hollow building blocks made of light concrete or pumice, have to be face-milled on their lower or upper planes.
According to prior-art methods the bricks to be milled are transported by means of a conveyor belt. Two milling shafts which contain the milling blades are thereby mounted above each other on a frame and the bricks are sent through the two cutters, whereby the upper and lower planes are simultaneously cut to the desired dimensions.
This prior-art method has the disadvantage that the grooves on the upper and the lower planes are of different depths. The total height of the stone is predetermined by adjusting the distance between the two milling shafts. However, due to the different density of the concrete in the brick (in the lower area the density is higher) the brick is deflected from the milling shafts to some extent, thus resulting in a difference in the depth of the grooves. Furthermore, it is disadvantageous that such arrangement works imprecise with respect to the total height of the brick and is susceptible to breakdowns, since the milling shafts are capable of flexing.